diff --git a/dateutil/test/test_isoparser.py b/dateutil/test/test_isoparser.py
index ebe16c400..e81db3a4a 100644
--- a/dateutil/test/test_isoparser.py
+++ b/dateutil/test/test_isoparser.py
@@ -306,7 +306,7 @@ def test_isoparser_invalid_sep(sep):
 
 
 # This only fails on Python 3
-@pytest.mark.xfail(six.PY3, reason="Fails on Python 3 only")
+@pytest.mark.xfail(not six.PY2, reason="Fails on Python 3 only")
 def test_isoparser_byte_sep():
     dt = datetime(2017, 12, 6, 12, 30, 45)
     dt_str = dt.isoformat(sep=str('T'))
@@ -356,7 +356,7 @@ def __make_date_examples():
         date(2016, 2, 1)
     ]
 
-    if six.PY3:
+    if not six.PY2:
         # strftime does not support dates before 1900 in Python 2
         dates_no_day.append(date(1000, 11, 1))
 
diff --git a/dateutil/test/test_parser.py b/dateutil/test/test_parser.py
index 6cdc27f3f..a5e0a4784 100644
--- a/dateutil/test/test_parser.py
+++ b/dateutil/test/test_parser.py
@@ -14,7 +14,7 @@
 
 from ._common import TZEnvContext
 
-from six import assertRaisesRegex, PY3
+from six import assertRaisesRegex, PY2
 from io import StringIO
 
 import pytest
@@ -462,7 +462,7 @@ def testDateCommandFormatReversed(self):
                                   tzinfo=self.brsttz))
 
     def testDateCommandFormatWithLong(self):
-        if not PY3:
+        if PY2:
             self.assertEqual(parse("Thu Sep 25 10:36:28 BRST 2003",
                                    tzinfos={"BRST": long(-10800)}),
                              datetime(2003, 9, 25, 10, 36, 28,
diff --git a/dateutil/test/test_rrule.py b/dateutil/test/test_rrule.py
index 9dfa5444b..b22a32960 100644
--- a/dateutil/test/test_rrule.py
+++ b/dateutil/test/test_rrule.py
@@ -4,7 +4,7 @@
 
 from datetime import datetime, date
 import unittest
-from six import PY3
+from six import PY2
 
 from dateutil import tz
 from dateutil.rrule import (
@@ -2284,7 +2284,7 @@ def testSecondlyByHourAndMinuteAndSecondBug(self):
                           datetime(2010, 3, 22, 14, 1)])
 
     def testLongIntegers(self):
-        if not PY3:  # There is no longs in python3
+        if PY2:  # There is no longs in python3
             self.assertEqual(list(rrule(MINUTELY,
                                   count=long(2),
                                   interval=long(2),
@@ -4579,7 +4579,7 @@ def testToStrWithWkSt(self):
                               dtstart=datetime(1997, 9, 2, 9, 0)))
 
     def testToStrLongIntegers(self):
-        if not PY3:  # There is no longs in python3
+        if PY2:  # There is no longs in python3
             self._rrulestr_reverse_test(rrule(MINUTELY,
                                   count=long(2),
                                   interval=long(2),